Anti-siphonic device



Filed Feb. 9, 1960 INVENTOR Charles W Muskeg J1:

BY M 1 ATTORN EY ilnited v btates Patent @tiice 3,@Z5,87fl Patented Mar.29, 19%2 3,025,870 ANTI-SEPHONIC DEVICE Charles W. Mackey, l ra,(Zheshire, Conn, assignor to Scovill Manufacturing Company, Waterbury,Conn, a corporation of Connecticut Filed Feb. 9, 1960, Ser. No. 7,643 3Claims. (Cl. 137-217) This invention relates to an anti-siphon devicefor preventing back-flow of a fluid through a fluid supply line thatfills a storage tank. For purposes of illustration, the device will bedescribed in conjunction with a ball-cock valve, but it is to beunderstood that the invention is clearly applicable to otherinstallations.

The anti-siphon devices in present day use consist mainly of two types:Those that have air intake ports at the top of the valve and those thathave air intake ports at the bottom. The first-named group, with theintake ports at the top, depend upon the incoming fluid to lift aport-sealing member upwardly until it closes oif said ports. When apressure reduction takes place, the portsealing member will drop bygravity and open said ports to the atmosphere. One of the principalobjections to this type of device is that there is a delay between thetime fluid is admitted to the valve and the closing off of the ventports in the top of the valve. This results in water splashing upwardlyout of the vent ports and many times out of the storage tank itself,thereby wetting the walls and floor around said tank.

The second type of vacuum breaker noted above has the vent ports locatedat the bottom of the device and employs a port-sealing member that dropsinto position by gravity and uses the reduced pressure above saidsealing member and the force of the incoming air to raise said member,thereby admitting air to the system.

There are several drawbacks to prior devices of this type:

First of all, the vent ports are always closed unless a reduction offluid pressure causes the port-sealing member to be lifted off its seat.If no such fluid pressure reduction takes place for a considerablelength of time, the sealing member may actually become stuck to its seatand be unable to move when a pressure reduction does occur, therebyrendering the device useless.

Secondly, the sealing member may be held in sealing position by normalsurface tension of the water, thereby causing enough delay to permitsome back-flow of fluid into the supply line.

A third fault common to both of the above types concerns the toleranceor clearance between moving parts. It is, of course, necessary to locatethe port-sealing members so that they will be centered with respect tothe air vent ports to insure proper closing of said ports. This normallyrequires fairly small clearance between moving parts. Small particles ofdirt or sand entering the antisiphon unit can work between the movingparts causing said parts to stick, thus making the unit inoperative.

An object of the present invention is to provide an improved anti-siphondevice where the air inlet ports are at the bottom but which will bereliable in operation.

Another object is to provide an improved means for admitting air intothe supply lines instantly when the pressure in said lines is reducedbelow atmospheric pressure. I

A further object is to provide an improved anti-siphon device which willavoid or eliminate the above-mentioned drawbacks to prior anti-siphondevices, and at the same time, be simple and economical to produce, withno complex castings and with few parts.

Another object is to provide an anti-siphon device in which the movingparts have a liberal clearance so that any small particles of dirt orsand that may enter the unit will not cause sticking or jamming of saidpart-s.

Other objects and advantages of this invention will be apparent from thefollowing description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a vertical cross-sectional View of an antisiphon unitembodying my invention as it appears in its normally inactive positionand attached to a ball-cock valve that is shown in dotted outline;

FIG. 2 is a vertical cross-sectional view of the unit as it appears whenthe tank to which it is attached is being filled;

FIG. 3 is a vertical sectional view of the unit as it appears when thepressure in the supply line has fallen below atmospheric pressure; and,

FIG. 4 is a bottom view of the anti-siphon unit.

In the drawing, the numeral 10 designates generally a ball-cock valve ofthe type commonly found in the conventional toilet storage tank,consisting of a valve body 11 that is attached to a water supply line12. A valve 13 is operated by the usual linkage 14 under the control ofa float 15. The valve body 11 has an internally threaded outlet 16 towhich my anti-siphon unit 17 may be attached.

The anti-siphon unit 17 has a valve body 18 within which is formed acylindrical chamber 19 that is connected to the outlet 16 of theball-cock valve by the nipple 20. This nipple, which may be formedintegrally with the valve body, is angled as shown so that the body ofthe antisiphon unit is above the threaded connection 16 on the inletvalve, the center of which connection is normally the high-water levelof the tank. This insures location of the anti-siphon unit above thewater level without requiring an unnecessarily high tank. The chamber 19is open at the bottom and has a short internally threaded section 21into which is fitted a closure plate 22 that has a complementary threadon its peripheral surface.

A hollow cylindrical stem 23 that is provided with a central bore 24extends upwardly from the top surface of the closure plate 22 and has atits juncture with the top of said closure plate, an outwardly taperingor flared portion 25 for reasons that will appear later. It should benoted that when the closure plate 22 is assembled to the body 18, theupper end of the stem 23 is spaced from the top of the chamber 19.

A hexagonal boss 26 is provided on the lower surface of the closureplate 22 in axial alignment with the hollow stem 23 and has a threadedrecess 27 for receiving the threaded end of a discharge tube 28. Thebottom of the threaded recess 27 connects with the bore 24 of the stem23, thereby providing a smooth straight central passageway between thedischarge tube and the cylindrical chamber 19 of the anti-siphon unit. Aseries of vent ports 29, circularly arranged about the stem 23, allowcommunication between the atmosphere and chamber 19.

A sleeve 34} is loosely fitted around the stem 23 and has at its lowerend an enlarged portion 31 in which is formed a groove 32 for carrying aflexible disc 33 which may conveniently be made of rubber. The disc 33is somewhat smaller in diameter than the diameter of the chamber 19 butslightly larger in diameter than the diameter of the circle defined bythe outer edges of the vent ports 29 in the closure plate 22.

It is to be noted that the disc 33 is normally spaced somewhat from theupper surface of the closure plate 22 due to the spacing of the groove32 from the end of sleeve 3%} and the normal tendency of the disc 33 toremain in a flat state. The inside diameter of the sleeve 30 is suchthat when said sleeve is in its lowermost position, it will co-operatewith the tapered portion 25 of stem 23 to center the sleeve 30, andtherefore, disc 33, with re spect to the vent ports 29 and chamber 19.

A small boss 34- is located on the side of the valve body 18 andthreadedly receives the usual small toilet bowl refill tube 35 which isconnected to the chamber 19 by a reduced opening 36.

When no water is passing through the anti-siphon unit 17, the flexibledisc 33 is spaced slightly from the vent ports 29 so that the chamber 19is open to atmospheric pressure as seen in FIG. 1. Should the ball-cockvalve be opened at a time when the line pressure is reduced belowatmospheric pressure, there could be no back-flow of water through theball-cock because the anti-siphon unit is already vented to theatmosphere.

If the line pressure is only slightly below atmospheric pressure, thedisc 33 need only flex somewhat to allow suflicient air to enter thelines and satisfy any vacuum formed therein. If differential betweenline pressure and atmospheric pressure is quite high, the combination ofthe pressure reduction above the disc 33 in the chamber 19 and thevelocity of the incoming air striking the underside of the disc 33 willcause the entire disc 33 and sleeve 30 to be elevated as shown in FIG.3. This will accomplish two things: first, the top of sleeve 30 willcontact the top surface of chamber 19 thus reducing the area of saidchamber that is open to discharge tube 28 and thereby reducing thepossibility of drawing any water back through said discharge tube;secondly, the vent ports 29 will be opened wide to allow more air toenter the system.

Because the combined area of the vent ports 29 is greater than the areaof the nipple 20, any amount of vacuum formed in the lines can besatisfied by said vent ports. After the vacuum has been satisfied, thesleeve 30 will drop to its lowermost position once again. When the lowerend of the sleeve 30 comes down, the flared portion 25 of the stem 23will center the sleeve with respect to ports 29 and chamber 19.

When the toilet storage tank is being filled, the antisiphon unit willappear as shown in FIG. 2. The water from the ball-cock valve will flowthrough the nipple 20 and enter the chamber 19 where the water pressurewill cause the flexible disc 33 to be deformed downwardly, therebysealing the vent ports 20. The water will completely fill the chamber 19and then exit through bore 24 of the stem 23 and into the discharge tube28 from which it will enter the toilet storage tank. While the storagetank is being filled, a small amount of Water will be discharged throughthe opening 36 and refill tube 35 to refill the toilet bowl in the usualmanner.

Should there be a sudden failure of pressure while the storage tank isbeing filled, the disc 33 will, because of its resilient nature,immediately flex upwardly to assume the position shown in FIG. 1 andthen, dependent upon the degree of pressure reduction, either flexslightly or raise upwardly as described above.

The spacing of the flexible disc 33 from the upper surface of theclosure plate 22 obviates the possibility of surface tension or adhesioncausing a delay in the upward movement of the disc 33 and the relativelylarge tolerances between the stem 33 and sleeve 36 eliminates the dangerof small particles of dirt causing the mechanism to stick.

It can be seen that I have provided a simple eflicient anti-siphon unitthat is quick-acting and reliable in opera: tion as well as economicalto manufacture.

It is not desired to confine the invention to the exact form describedand shown herein, but it is desired to include all such forms as comewithin the scope of the appended claims.

What I claim is:

1. An anti-siphon device comprising a valve body having a cylindricalchamber therein and a nipple connecting said chamber to a fluid supplyunit, said chamber having an opening in its lower end, a closure platefitted into said opening, said plate having a series of portstherethrough, a hollow discharge stem projecting upwardly from the topsurface of said plate and into said chamber, a sleeve loosely fittedaround and slidable on said stem, at flexible disc of somewhat smallerdiameter than said chamber carried by said sleeve adjacent its lowerend, said disc in its normally inactive position being spaced slightlyabove the ports of said closure plate, and means for centralizing saidsleeve when it is in its lower-most position.

2. An anti-siphon device comprising a valve body having a chambertherein and a nipple connecting said chamber to a fluid supply unit,said chamber having an opening in its bottom, a closure plate fittedinto said opening, said plate having a series of ports therethrough, astem projecting upwardly from the top surface of said plate and intosaid chamber, said stem having a central bore, a sleeve loosely fittedaround and slidable on said stem, a flexible disc somewhat smaller thansaid chamber carried by said sleeve adjacent its lower end, said disc inits normally inactive position being spaced slightly above the ports ofsaid closure plate, said disc being adapted to flex downwardly underfluid pressure to seal said ports, said disc and sleeve being adapted tomove progressively upwardly as a unit along said stem as the fluidpressure in the valve body decreases below atmospheric pressure untilthe upper end of the sleeve seats against the top wall of said chamberto reduce the area of said chamber open to said bore.

3. An anti-siphon device comprising a hollow valve body adapted to beconnected to a water supply unit, said valve body being closed at thetop and having a plurality of vent ports at the bottom, a dischargeconnection at the bottom of said valve body, a hollow stern extendingupwardly into the valve body and communicating with said dischargeconnection, a vertically movable sleeve surrounding said stem, the wallsof the sleeve being spaced substantially from the stem, a disc offlexible material carried by the sleeve which in unstressed conditionextends over said vent ports in slightly spaced relation thereto,whereby pressure of water above said disc causes the disc to flex intosealing relation with said vent ports, and whereby a vacuum above thedisc will cause the disc to rise away from the ports to allow air toenter the valve body.

References Cited in the file of this patent UNITED STATES PATENTS162,598 Bailey Apr. 27, 1875 2,328,598 Anderson Sept. 7, 1943 2,777,464Mosely Ian. 15, 1957 FOREIGN PATENTS 783,323 Great Britain Sept. 18,1957

